MIC94310 Evaluation Board 200mA LDO with Ripple Blocker™ Technology General Description Getting Started The MIC94310 is a 200mA Low Dropout (LDO) regulator that provides high power supply ripple rejection (PSRR). This is important for applications where switching noise cannot be tolerated by sensitive downstream circuits such as in RF applications. The MIC94310 maintains high power supply ripple rejection (PSRR) with input voltage operating near the output voltage level to improve overall system efficiency. The MIC94310 operates from an input voltage of 1.8V to 3.6V. Datasheets and support documentation can be found on Micrel’s web site at www.micrel.com. Requirements The MIC94310 evaluation board requires an input power supply that is capable of delivering greater than 400mA at a voltage range of 1.8V to 3.6V. The output load can be either active or passive. • Connect an External Supply to VIN. Apply the desired input voltage to the VIN and ground terminal of the evaluation board, paying careful attention to polarity and supply voltage (1.8V ≤ VIN ≤ 3.6V). • Enable/Disable the MIC94310. The evaluation board is supplied with 100kΩ pull-up resistor to VIN for default on state. To disable the output, simply jumper the EN terminal to ground. • Connect the Load. Connect the load to the VOUT terminal and the ground terminal. The load can be either a passive (resistor) or active (electronic load). Be sure to monitor the output voltage at the VOUT terminal. Precautions The MIC94310 evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN terminal may damage the device. Ordering Information Part Number Description MIC94310-GYCS EV 200mA LDO Ripple Blocker™ CSP Package Evaluation Board VOUT=1.8V MIC94310-GYMT EV 200mA LDO Ripple Blocker™ Thin MLF® Package Evaluation Board VOUT=1.8V Ripple Blocker is a trademark of Micrel, Inc MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com February 2012 M9999-020912 (408) 944-0800 Micrel, Inc. MIC94310 Evaluation Board PSRR measurements may be made using either dedicated PSRR test equipment or with a PSRR interface board and a network analyzer. The network analyzer can sweep the AC frequency and perform a comparison measurement of the amplitude on the input and output. With this method, the network analyzer is configured for an A/R measurement. The difficulty arises when trying to impose the network analyzer’s AC signal with the DC input voltage to the MIC94310. The circuit shown in Figure 3 accomplishes this by using the MIC911 as a summing amplifier. The summing amplifier adds the VSUPPLY (DC voltage) and the network analyzers AC signal. As the network analyzers source is 50Ω impedance it may be neglected, the DC voltage seen at the noninverting side is half of the VSUPPLY voltage. The output is gained up by 2 with the 1kΩ resistor divider to the non-inverting side. This sums the AC and DC voltages with an overall gain of 1. Power Supply Ripple Rejection (PSRR) Measurements Figure 1 illustrates the frequency response of the MIC94310. PSRR COUT = 1µF 0 PSRR (dB) -20 -40 -60 IOUT = 200mA IOUT = 100mA -80 -100 VIN = 2.5V + 40mVpp IOUT = 10mA VOUT = 1.8V -120 10 1.E+02 100 1.E+03 1K 1.E+04 10K 1.E+05 100K 1.E+06 1M 1.E+07 10M 1.E+01 FREQUENCY (Hz) Figure 1. MIC94310 Ripple Blocker™ Frequency Response For high-frequency measurements (above 1MHz), careful attention must be made to the test set-up configuration as it is easy to introduce noise into the grounds which will give inaccurate measurements as shown in Figure 2. Figure 2. High-Frequency Noise on Measurement System The inductance of test probes connected to the evaluation board at higher frequencies becomes a factor which can create a differential between the device under test and test measurement system grounds. Adding a low-value resistor (2Ω) in series with the input capacitor to ground and utilizing a test measurement system capable of making differential measurements will help to reduce these effects. February 2012 Figure 3. Network Analyzer Set-Up 2 M9999-020912 (408) 944-0800 Micrel, Inc. MIC94310 Evaluation Board Evaluation Board Schematics Bill of Materials Item C1, C2 Part Number CL10B105KA8NNNC Manufacturer (1) Samsung (2) Description Qty. 1µF, 25V, X7R, Size 0603, ceramic capacitor 2 R1 CRCW0402100KFKEA Vishay 100KΩ, 1%, 1/16W, Size 0402 resistor 1 R2 CRCW04022R00FKED Vishay(2) 2Ω, 1%, 1/16W, Size 0402 resistor 1 200mA LDO with Ripple Blocker™ technology 1 MIC94310-xYCS U1 MIC94310-xYMT Micrel, Inc.(3) Notes: 1. Samsung: http://www.semlcr.com. 2. Vishay: www.vishay.com. 3. Micrel, Inc:: www.micrel.com. February 2012 3 M9999-020912 (408) 944-0800 Micrel, Inc. MIC94310 Evaluation Board PCB Layout Recommendations (CS Package) Top Layer Bottom Layer February 2012 4 M9999-020912 (408) 944-0800 Micrel, Inc. MIC94310 Evaluation Board PCB Layout Recommendations (MT Package) Top Layer Bottom Layer February 2012 5 M9999-020912 (408) 944-0800 Micrel, Inc. MIC94310 Evaluation Board MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB www.micrel.com Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2012 Micrel, Incorporated. February 2012 6 M9999-020912 (408) 944-0800